A thick, lively Amazonian fermented cassava drink. Cassava and sweet potato form a creamy base that develops gentle acidity as it rests, with just enough sweetness to keep it approachable and refreshing. A flavor deeply tied to hospitality in the Peruvian Amazon—and well worth the wait.
Peel the cassava and sweet potato, cut both into medium pieces, and remove the tough central fiber from the cassava. Cook them in most of the water for 25 to 30 minutes, until the cassava is completely tender, splitting at the edges, and crushes without resistance. Drain thoroughly and discard the cooking water.
Mash the cassava and sweet potato while still hot until fairly smooth; then gradually mix in the brown sugar and part of the clean water until you have a thick cream with no large chunks. Let it cool for 10 to 15 minutes, until the container feels warm rather than hot and strong steam has stopped rising.
Turn what you find into an experience you can actually bring to your kitchen.
Stir in the dry yeast once the mixture is warm, distributing it evenly. Transfer the base to a very clean glass jar, leaving some headspace, and rest the lid on top without sealing it airtight. Ferment at room temperature, away from direct sunlight, for 24 hours; by the end it should show some bubbling and a clean, lightly sweet-and-sour aroma. If you see mold, unusual colored growth, or detect a rotten smell, discard the entire batch.
Stir the masato and gradually add the remaining water. Blend in short batches until it is creamy and thick but still fluid enough to drink comfortably; it does not need to become completely smooth. Serve cool or at room temperature and refrigerate any leftovers to slow further fermentation. If it keeps its cassava body, gentle acidity, and a lightly sweet finish, it is right where it should be. And that’s it! Homemade masato. 😌
